Studies on plasmon characteristics and the local density of states of Au and Ag based nanoparticles

• Chemically pure Au, Ag, Ag@Au core–shell and Au–Ag bimetallic chain nanoparticles are prepared by laser ablation method.
• The I–V characteristics and the density of states derived from scanning tunneling microscopy measurements.
• An attempt has also been made to compare the current measurements done in the nanoscale with the surface plasmon characteristics.

Knowledge about the conductive properties and the local density of states of chemically pure Au, Ag, Ag@Au core–shell and Au–Ag bimetallic nanoparticles is technologically important. Herein, the I–V characteristics and the density of states derived from scanning tunneling microscopy measurements made under atmospheric conditions is reported. The nanoparticles in thin film form used in this study were prepared by laser ablation in water followed by drop and evaporation. The morphology of the surface of the nanostructures was observed from optimizing tunneling current in each case. The monometallic Au and Ag particles shows almost similar current characteristics as well as discrete energy states but the slope of I–V characteristics was different for bimetallic structures. An attempt has also been made to compare the current measurements done in the nanoscale with the surface plasmon characteristics.